Angle Resolved Photoemission from Chemisorbed Layers: Further Theoretical Considerations
John William Gadzuk
In recent theoretical work by Gadzuk and by Liebsch, the importance of angle resolved photoemission studies of surfaces and chemisorbed atoms has been demonstrated. In the theory due to Gadzuk, the role of the initial state in the photoemission process has been emphasized, whereas in the theory due to Liebsch, the role of the final state is stressed in determining a photoemission angular distribution (PAD) from chemisorbed atoms. Here it is shown what conditions favor initial versus final state dominance. In both theories, the PAD is calculated for an isolated chemisorbed atom or surface molecule complex. It is shown how two-dimensional band effects due to adatomadatom interactions modify (or do not modify) the PAD.